Edward b



strat ffies.,

IMPRUVEMENT 1N meme sentir-HEADS.

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TO ALL WHOM IT MAY CONCERN:

Be it known that I, EDWARD B. FIS-H, of Glenns Falls, in the -county" oi' Warren, and State of'New Yoifl't, i'

have invented a new and useful Improvement in Screws; and I do hereby declare that the following is a. fulT, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, referencebeing had to the accompanying drawings, forming a part of this specification.

A great deal of annoyance and inconvenience is occasioned when inserting screws into joincrs and coach makers work, by the screw-driver slipping out of the countersink in the screw-heath" and .this often occurs, however careful the workman may be, to an extent to greatly mar the job or work. The object, therefore, of my -invention is to so construct-a screw/:md adapt to it the end of the driving-tool, esto preclude the conti' gency of the driving-tool slipping. My invention consists in ccnstructingscrews with a cavity or indentation at about the middle ofthe contersink in the head of the screw, and the same being intended for receiving a projecting piece on the end of a screw-driver, whereby there will be'but little if any'liability of the driving-tool slipping out of the countersink in the screw whilst in the act of driving the'screw.' In the accompanying drawingf- Figure 1 is a'central longitudinal section of screw made according to my invention, taken on the plane of the line x x, g. 2.

Figure 2 is a top v iew of the screw.

Figure 3 is a side elevation of a driving-tool adapted to said screw.

Similar letters oi' reference indicate like parts.

Adesignates an ordinary screw, the countersink on its head being indicated by the letter a, iig. 2. At

l about the centre diametrlically of the head, and at about the centre longitudinally of the countersink'` in the screw, I form a cavity, @the said cavity being such that it can be made at thetimc the coun-tersiuk is cut in the screw, so as not to increase Iche expense'of the screw in any material degree. In g. 4 Ihave illustrated a screw-driver which may be used for driving my screw. Y B`designates the driver, which has on its end or edge la" projecting piece, c, Vwhichxlatter is intended to sink into the cavity Z ofthe screw. By thus constructing :r screw it will not be so changed that it cannot be operated as an ordinary screw, and in addition to this it possesses the great advantage that by usingin connection with it a. properlyconstructed screw-driver B, it can bedriven in 'and drawn out without any liability of the driver slipping out of the countcrsiuk. I am aware that nuts with What I claim as new, and desire to secure by Letters Patent, is A nickcd screw, provided with a cavity, b, in its head, substantially as specified.

notchescut in opposite edges, and a screw-driver to match, have been used, but I do not claim any such devices.

EDWARD B. FISH.

Witnesses:

C. R. CAMERON, A. W. MORGAN, Jr, 

